U can write about green children

or atlantis
or bermuda triangle
everyone will like the story of the green children...although it sounds false
Mystery is, not knowing the truth about some event that happened or about a person. We do not anything about the life after death and what happens after. It is a mystery still.  Mystery is absence of any information on a topic or about a person of interest to us or to the society.

   People like mysteries. It thrills most of us.  The suspense in a mystery thriller story holds the persons attention strongly, holds the heart beat, all the concentration and focus of the persons.  It is just basically in the human nature itself.  We just feel intrigued by suspense and we cannot tolerate it in the nerves for a long time.   Some people even could face heart-attacks due to the stress on the nervous system.  After a mystery is unravelled, we feel so relieved in the nerves and happy in the mind.

   Many serials on TV, magazines, thriller books, and cinemas do well because of the tense excitement that they create in the minds of the audience during some moments.   They cash in on the weak points of the audience.  Usually darkness, ghosts, haunted houses previous births, aliens from spaces, and other topics form the story lines of the mystery thrillers.  There are famous film makers who make suspense thrillers. 

   The persons who solve mysteries are very accomplished, respected and fantasied.  Often people are crazy after the heroes.  Mysteries are everyday lives for the police force and detectives.  In a way the scientists are also trying to solve mysteries of the world in their everyday efforts.